Recycling control system and apparatus for oil burners and the like



Jan. l, 1935. J. MCK. REILEY 1,986,013,

RECYCLING CONTROL SYSTEM AND APPARATUS FOR OIL BURNERS AND THE LIKE Filed Feb. 248, 195o s sheets-sheet 1 f To noma PRIN 3 Sheets-Sheet 2 Jan. 1, 1935. .1. McK. REILEY RECYCLING CONTROL SYSTEM AND APPARATUS FOR OIL BURNERS AND THE LIKE Filed Feb. 2e, 195o ,mm W. \& w n

m k HU ,U N Ik En] o\\ Em n J Jan- '1; 19357 .1. MCK. REILEY O 11,986,013

RECYCLING CONTROL SYSTEM AND APPARATUS FOR OIL BURNERS AND THE LIKE Filed Feb. 28, 1930 3 Sheets-Sheet 3 A www Patented Jan. 1, 1935 RECYCLING CONTROL SYSTEM AND APPA- RATUS FOR OIL BURNERS AND THE LIKE James McK. Belley, Merton, Pa., asslgnor, `by

mcsne assignments, to General Electric Company, a corporation of New York Application February V28, 1930, Serial No. 432,145

12 claims.

The present invention relates to control apparatus for heating systems operated by oil burners, gas burners and the like, and particularly refers to means for controlling the quantity of fuel injected into the combustion chamber at any one operation to the safe amount which can be expanded in the chamber underv any conditions and for repeating the operation a predetermined number of cycles to overcome the difficulties in starting ignition.

The principal object of the invention is to provide means for automatically controlling the functions of a heating system in apositive and safe manner in accordance with the temperature demands or requirements.

Another object is to provide means for automatically limiting the starting ignition attempts to periods o f short duration and repeating the starting ignition attempts a predetermined number of times or until the fuel has been ignited and for shutting down the entire system if the fuel fails to ignite at the last attempt.

.Another vobject is to provide positive timing means independent of externaleifects for controlling the starting attempts to ignite the fuel at predetermined intervals and also for control.- ling thetime range of operation of thermostats associated with the heating system for maintaining the temperature constant.v

Another object is to provide positive electrically-operate'd timing means dependent solely upon frequency as, for example, a synchronous motor which is independentof voltage variations.

lAnother object is to provide means for automatically resetting the control apparatus of the system to its initial or safe condition when ignition has been established.

A further object is to vprovide means for man- ,ually resetting the control system to its original condition in case ignition fails tov take place at the last attempt. f b a A still further Objectis to provide means for automatically resettingv thev control apparatus of the systemgto its initial or safe condition incase of power failures or loss of flame orcombustion.

of Fig. 1 showing the furnace and associated control apparatus;

Fig. 3 is a front view of the recycler used in the system;

Fig. 4 is a side view thereof looking at the device from the left;

Fig. 5 is another end view looking at the device from the right;

Fig. 6 is a sectional view taken on line H of Fig. 3; and

Fig. '7 is another sectional view taken on the line '1-7 of Fig. 3.

Fig. 8 shows a modification of the cam for shifting the control from the day to the night thermostats.

Existing control apparatus for oil burners, for example, permits only one attempt for the burner to ignite the fuel and get under way. The reason for this is brought about by the necessity for eliminating minor service diiculties generally due to loss of head on the fuel pump, extra viscosity of the oil inithe case of an oil burner, leaking foot valves, water slugs inthe oil line, temporary ignition troubles, failure of the blower supplying air to the combustion chamber,l etc. In

the case of gas burners, other analogous diicull allowed to satisfactorily eliminate them, under certain conditions,` 'the burner will produce a flare-back, causing-the furnace doors to be blown vcgpen and, in some cases, the Apuff or explosion produced may be suflicient to ycause 'damage to the heater itself.` f

The present invention providesmeansr for controlling `the quantity of fuelfinjected` into the y combustion chamber-atlany one operation to the safe amount in theiform of a shortf'fshotm'or jet which can be expanded in the combustion chamber under any conditionsv and repeating the o'p-'f eration as many times as desired to provide sufculties outlined above with sufficient time 1be'- f tween pumping:v Yperiods to allow "the 'fuel Biff sprayed, atomized'or vaporiied inthe pumping periodsfto bedis'posd-ofl either by lthejnatur'all'l f draft of the boilerif theboiler is hot'or to 'be-condensed against the.cold surfaces ofthecombus- In order to carry'out 'this method' of `control-I ling thequantityof fuel injectedV toa safe amount,

it is essential to provide positive timing .means for the operations of the control mechanismwhich is unaffected by external influences and, thereby, controlling the operations of the burner itself. To insure a positive means of timing, the invention contemplates in the present instance, the provision of an electrically-operated device such as a small synchronous motor for driving a cam and which accurately and repeatedly gives the same time cycle and which is not affected by voltage variations but depends solely `upon the frequency of an alternating current supply thereto for its operation rather than employing the usual means for obtaining time effects in existing control apparatus by the so-called warp switches or thermaltiming means. Therefore, one of the features of the invention is the application of -a synchronous or frequency motor to4 control apparatus for timing purposes and for controlling the starting periods of the burner or the time range of the thermostat settings of the system or both.

Referring to Figs. 1 and 2 of the drawings, the system comprises a thermostat A, a starting transformer B, a relay C, a timing cam D, a synchronous motor M, a thermostat control cam E, a recycling mechanism F, a lock transformer J, furnace thermostat H, and ignition transformer I. II'he furnace thermostat H, in the present instance, may be located in the combustion chamber 78 of the furnace '7'7 (Fig. 2) or at anyother suitable'location at which the direct heat of the furnace may affect it when combustion is established. The furnace 77 is, of course, located in the basement below the floor-82 and transmits heat through the hot-water or steam-pipes '79 and to the radiator 81 which islocated in the room with thermostat A. Of course, it is understood that the control circuit and apparatus of the invention are applicable to furnaces of any type of heating systems, such as hot air, vapor, pipeless furnace, etc., without departing from the scope of the invention. `The combustion chamber 78 may be supplied with sprayed, atomized, vaporized or gaseous fuel from the supply tank 90, or any other source of fuel supply, by means of the pump 86 through pipe 85 and nozzle or burner 84.

An air pump 88 supplies the necessary combus tion air. The fuel is then adapted to be ignited by an electric spark produced at the spark gap 83 across the secondary of ignition transformer I when it is energized. 'I'he ignition transformer I may be located in the vicinity of the furnace 77 with its secondary leads terminating in a spark gap 83 in 'the `combustion chamber 78. The thermostat A comprises two heat-responsive elements 1 and 2 which are adapted to open and close contacts 3-,f-.4` and 5,-6",frespectively, inaccordance with temperature changes at a desired location as, for example, a room in a dwelling or other. building. As indicated in the figure, the elements 1 and 2 of thermostat A are adapted to close the circuit through the secondary of the starting transformer B when they engage contacts 4 or 6 throughthe conductors '7 or 8, the conductor 9, the winding 10 of relay C, conductor 11, contacts 12 and 13, which may beopened and closed by means of the timing'cam D, through conductor 22 is provided on the. cam E, which when it strikes the follower ,20, raises it, making a circuit through contacts 16 and 17 to the thermal element 2. Element 1 may be adjusted to be actuated at onetemperature, while element 2 may be adjusted to respond to another temperature and, in this instance, responds to a lower temperature than element 1 so that element 1 may be utilized during the day hours indicated as Day range" when a higher temperature is required in the room and element 2 may be utilized during the night hours indicated as Night range when a lower temperature is generally desired. The cam E is designed to rotate one revolution in twentyfour hours and the proportions of the facings 21 and 22 of the cam may be designed for any interval desired. For example, the face portion 21 may be made so as to constitute a longer path of travel for the follower 20 than the face portion 22 in order that the Ielement 1 of thermostat A may be utilized for a'longer period than element 2. The cam may easily be designed to be adjustable so that the lengths of the portions 21 and 22 may be varied to any predetermined desired extent. In Fig. 8 is shown such a cam. It will be noted that the cam comprises two parts, the part E and the part E1 provided with collars 102 and 103 and having raised portions 22' and 221. The parts are mounted adjacent each other on the cam shaft S and may be rotated with respect to each other on the camshaft if setscrews and 101 are released. Thus, it will be seen that by properly shifting the two parts with respect to each other, the raised portions 22 and 221 will together provide a longer .raised portion than eitherl one individually, The cam E may be rotated by means of the motor M, which is of a Well-known type of. a synchronous motor having a shaft geared thereto fora speed of one revolution per minute, and by means of suitable ,gears the cam may be given a speed of one revolution in twentyfour hours.

The timing cam D is also rotated by means of the synchronous motor M and, by means of an- 23, the contacts 12 and 13 are closed, while when the follower is raised, by 'the faces 25 of the cam, the follower 24 causes the contacts 12 and 13 to be opened.

rotates a half a-revolutin per minute and the' recesses 23 are'90 apart, the contacts l2, 13 -will be closed every thirty seconds and remain It will beseen that since the cam D closed for a relatively short interval and opened again by the; follower 24 when it strikeslthe raised portions 25 of the cam. vThe timing of the closing of the contacts 12 and 13 is positive and accurate-because ofthe fact that the motor -M is a synchronous motor and depends solely upon fre- -q'uency for its speed. As long as the frequency remains constant, its speed remains constant, in spite of any voltage variations onthe line. It may be designed to operate on a frequency of sixty cycles or anyother suitable frequency commercially available in practice. The motor M is en- .ergized from the volt alternating current source of the desired frequency from the terminalv L through-conductor 26, conductor 27, conductor 28, through conductor 29 to the other side of the 110 volt line to the terminal G which in the present instance is grounded.

at all 'times and never interrupted. When cams Obviously separate 4synchronous motors could.V

be usedto drive cams-'D and Einstead of a single atdfferent positions; It should `be noted also that vthe design of'cam D orl the speed of its shaft may be varied'to give any desired duration and 'frequency to the open and closed periods of contacts 12 and 13.`

The circuit of the frequency motor M is closed D and E are in the positions indicated, element 1 of thermostat A is in circuit and the heating system is operated on the daylight range, the circuit being made from elementi through conductor 18, contacts 15 and 16, conductor 1 4, contacts 13 and 12, conductor 11, winding 10 of relay C, conductor 9 through the secondaryof the starting transformer B, conductor 8, conductor 7 and through contact 4 back to element 1. When the circuit is thus closed, the winding 10 of the relay C becomes energized and also the secondary of the starting transformer B. The primary of transformer B is energized from terminal L through conductor 26, contacts A27' and 28', conductor 29' and through conductor 30 to the terminal G of the other side of the line. However, no current flows in the secondary until its cir cuit is closed by means of the contacts 12 and 13.- As soon as the circuit is closed, the Winding 10 of relay C becomes energized, as hereinbefore stated, closing the contacts 31 and 32 of the relay which closes the circuit of the motor 87 of the pumpv 86 and the primary of the ignition transformer I. The circuit of the pump motor 87 is made from terminal L through conductor 26, contacts 27' and 28', conductor 29', conductor 33, contacts 32 and 31, conductor 34, conductor 35, terminal M1, through the motor via conductors 35' and 36' to terminal M2, and through conductor 36 back to terminal G of the 110 volt line. While the motor circuit is momentarily closed, it causes the fuel pump 87 to inject a short shot of fuel into the combustion chamber '78 of the furnace 77 through burner 84 Where it is adapted to be ignited by a spark produced across the gap 83 of the secondary of ignition transformer I. Simultaneously, the primary of the transformer I is closed from vthe junction point 37 of conductors 34 and 35,

through conductor 38, through thermal element 39 of thermostat H, contact 40, conductor 41, through the primary Winding of I and through conductor 29 to terminal G. The secondary of the ignition transformer I produces the required spark in the combustion chamber and if the conditions are exact, the fuel in thechamber will be ignited and combustion esgblished. However, if conditions were such that ignition would not take place in the combustion chamber at the instant that the contacts 31 and 32 of the relay C are closed, the cam D opens contacts 12 and 13, thus deenergizing the winding 10 and breaking the circuit of the primary of transformer I and of the pump motor 87. The short "shot of fuel which had been injected by the pump is then permitted to escape through the draft of the furnace if the furnace is hot or to condense in the combustion chamber vif the furnace is cold as explained' hereinbefore. The fact that the fuel is injected in jpst a short shot or in other words just the necessary quantity required to start ignition and prevented from continuing to` be injected, large quantities of fuel are prevented from accumulating in the chamber which when ignition would nally take place might cause an explosion sufficiently great to destroy the f ur`- nace and possibly wreck a portion of the building in which it may be located, As cam D continues to rotate the contacts 12 and 13A are again. closed by the cam D, thewinding 10 is again energized' the arm42 of the relay C isattracted thereby and contacts 31 and 32 are again closed and another jet `of fuel is injectedinto the combustion chamber and a spark established across the secondary of transformer I. As the arm 42 is attracted by theA winding 10, it actuates aconnecting arm 71 which is. connected to arm 42 and causes the rod 44 ofthe recycler F to be moved upward bythe pawl 45. The rod 44 may be cylindrical inl shape 'and provided with circumferential grooves 46 which constitute sort of a ratchet which is engaged inone groove at a time, leach time that` the pawl is actuated by the arm 42 through connecting rod 71. As the rod 44 rises one notch, it is held in place by means of a spring element 47. After the cam D has closed the contacts 12 and 13 five times or more, depending on the number of grooves provided on rod 44, and ignition has not been established, the rod 44 will nally be raised to such a position that the head 48 of the rod 44 will strike the pivot arm 49, causing the contacts 27 and 28' to be opened by virtue of the spring qualities of contact arm 27'. As soon as contacts-,27' and 28 are opened, the primary of the transformer B is open-circuited and the secondary thereof thereby deenergized, causing the deenergization of winding 10 and the release of the arm 42 of the relay C. No circuits can now be established until the contacts 27 and 28 are reclosed or reset manually. 'I'his function prevents the taking place of spontaneous ignition which might otherwise be produced. The repeated notching action just described causes the rod 44 and associated parts to function as an automatic mechanism for accurately counting the number of attempts to establish combustion and the number of these attempts is limited accurately by the number of grooves provided on the rod 44. If, however, in any cycle of the cam D, combustion is established, the thermal switch mechanism or ame detector H, which may be located in the combustion chamber, will operate, moving its thermostat 39 from the contact 40 which is in the cold position to the contact 50 or the hot position, causing a circuit to be made from terminal L through conductor 26, contacts 27' and 28', conductor 29', conductor 33, contacts 31 and 32, conductor 34, junction 37, conductor 38, element 39, contact 50, conductor 51, through the primary of the locking transformer J, through conductor 52 and through conductor 30 back to the terminal G on the other side of the 110 volt line. The` circuit of the primary of the transformer J being closed causes the energization of its secondary and also of the winding 10 of the relay C. The winding 10 now becomes permanently energized or locked by reason of the primary of the transformer J being energized through the thermostat H, thus keeping the contacts 31, 32 closed as long as combustion is maintained. At the same time, a circuit is completed from the junction point 37 through conductor 53 of the locking transformer J, conductor 54 through the Winding 55 of the recycler F, through conductor 56 and through conductors 28 and 29 back to terminal G of the other side of the line. The energization of the winding 55 causes the rod 57 to be pulled down against the tension of the spring 58 which is seated between collars 59 and.60 on the rod 57 and causes the spreading apart of pawl 45 and spring element 47 to disengage the rod 44 and allowing it to drop to its original position against the guide 61. Thus, it will be seen that the recycler is automatically reset by means of the winding 55 when combustion is established. If combustion should cease for any reason, the thermostat l- I will again be actuated to its cold position against contact 40 thereby breaking the contact between the element .39 and contact 50, causing the deenergization of the primary of transformer J, thereby deenergizing l the winding 10 by virtue of the secondary of transheat, nothing happens until the thermostat A,

again calls for heat since the circuit through the electro-magnet l0 is broken at the thermostat. Also in case of power failure at the terminals L and G, the transformer J will be deenergized and the whole system rendered inoperative.

When combustion has been started and maintained, the temperature in the region in thermostat A will rise until-the temperature is reached for which the element 1 is set, at which time, the element 1 will break the contact 4 and close the 'contact 3. As soon as contact 3 is closed, the winding 10 becomes short-circuited through element 1, contact 3, conductor 61, conductor 9,

to one side of the secondary of transformer J, from the other side thereof to conductor 11, contacts 12, 13, conductor 14, contacts 16 Aand 15 and through conductor 18 back to' element 1. The short-circuiting of the winding 10 causes the arm 42 of the relay C to be released and the circuit 'of the pump motor. to be broken by contacts 31 and 32. When the temperature drops below the setting of the thermostat, the element 1 again engages contact 4 and the system set into operation as before.

Referring toFigs. 3 to 7, the recycler F comprises an insulating panel 63 on which are mounted the cylindrical casing 65, which holds the relay winding 55 (Fig. 1), the terminal binding posts 66 and 67, which are adapted to be connected to the primary of the starting transformer B, and the terminal L of one side of the 110 volt supply line, respectively, as indicated in Fig. 1. To the terminal 67 is connected a spring contact element 68'on which is mounted the contact 27 which is adapted to engage contact 28 and close the circuit through terminal 66. The normal position of the contact element 68 is such that contacts 27 and 28' are in closed relation and the element 68 is maintained in this position by means of the tooth 69' on the locking element 69 which is fastened to the panel 63,by means of the bracket70. When the locking element 69 is raised, the element 68 moves to the left by virtue of the spring action thereof and breaks the contacts 27' and 28'. The locking element 69 is adapted to be raised by the knob 48 which is integral with the rod 44. The rod 44 is provided with the circumferential grooves 46 which form a sort of rack and the grooves are adapted to be engaged by 'the pawl 45 to raise the rod 44 one notch each time that the rod 43 is actuated by means of the arm 71 which is adapted to be connected to the armature 42 of the relay C (Fig. 1). It will be apparent that each time that the relay 42 closes the contacts 31, 32, the arm 71 moves with it, thereby'actuating the rod 43 and the pawl which are pivotally mounted in the bracket 72 by means of the rod 73. As the pawl 45 raises the rod 44 one notch, the rod is held in that position by means of the spring element 47 which b ears against the rod 44 at an angle thereto so that its upper edge engages the rst notch. When the armature 43 of the relay C is released, the weight 74 functions to drop the pawl 45 to its lowered position. After the armature 42 of the relay C has been actuatedfive times in the present instance, or as many /times asthere are circumferential groovesA 46 on the rod 44, the rod 44 will have reached its maximum raised position, that is, the last circumferential groove is engaged by the pawl 45 and raised so that the knob 48 strikes the locking element 69, thereby releasing the spring element 68 from its locked position and breaking the contacts 27 and 28', as explained in the description of Fig. 1. .The breaking of the contacts 27 and 28' breaks the 110 volt supply circuit, so that all of the elements of the system are rendered inoperative with the exception of frequency motor M which is in circuit at all times. An armature57 is provided which is adapted to be actuated by the winding of the relay 65, as explainedhereinbefore and ignition has been established in the combustion chamber. In that case, the armature 57 is drawn downward against the force of the spring 58 which is compressed, causing the tapered end 75 of the rod 76 to pass between the pawl 45 and spring element 47, thereby spreading them sumciently to permit the rod 44 to drop to its original position, thereby resetting the recycler automatically'so that it will be available for operation the next time that ignition is to be again initiated. The rod 76 is, of course, attached to the armature 57 in order that it may be actuated thereby.

yWhen winding 55 of the relay 65 is deenergized,

the armature 57 is returned to its normally raised position by means of the spring 58 which is confined between the collar 60 and the nut 59. As lthe rod 76 is withdrawn from between the pawl 45 and the spring element 47, the spring element is caused to bear against the rod 44. The rod 44 is guided in its travel by means of the guides 61 and 62 which are integral with the bracket 72.

It is believed that the operation4 of the recycler F will be apparent from the foregoing description together with the description of the operation of the entire system which has been explainedwlth respect to Fig. 1. I

While I have shown only one embodiment of the control system and the apparatus connected therewith, other changes and modifications may be apparent therein to those skilled in the art without departing from the scope of the invention and I, therefore, desire to be limited only by the scope of the appended claims.

I claim:

1. The combination with a heating system including means for feeding fuel, and an igniter, of a control system therefor comprising means for controlling said fuel-feeding means and igniter to attempt to initiate combustion at predetermined temperature conditions, means including electromagnetic means and intermittent energizing means therefor for rendering said secondmentioned means effective a predetermined numberl of times at selected intervals for periods of short duration, and means operative with said v v 1,98"6,v013

ycam mechanism 4for operating said controlling f electromagnetic. meansforrendering said control system ineffective whenf combustion failsto take place during the last time that -said second-meni, 2.. The cmbinationlwith a, heating system 'in-v cluding means'for feeding fuel and an igniter, of a control system thereforcomp'rising means for controlling said'V fuel-feeding' 'means and igniter to. attempt to initiatecombus'tion at predetermined temperature conditions, electromagnetic means for rendering said .second-mentioned means effective, Aintermittent circuit controlling means for causing the energization of said electromagnetic means .whereby it' is actuated at selected intervals for periods `of short duration, positive timing means for actuating said fourthmentioned means to produce the selected intervals, means for limiting the number of times said electromagnetic means may be actuated and operative therewith, and means adapted to be actuated by said last-mentioned means for rendering said control system ineffective when combustion fails to take place during the last actuation of said electromagnetic means.

3. The combination with a heating system including means for feeding fuel and an igniter, of a control system therefor comprising means for controlling said fuel-feeding means and igniter to attempt to initiate combustion in said first-mentioned means at predetermined temperature conditions,` electromagnetic means for rendering said second-mentioned means effective, intermittent circuit controlling means for causing the energization of said electromagnetic means whereby it is actuated at selected intervals for periods of short duration, electrically controlled timing means for actuating said fourth-,mentioned means to produce the selected intervals, means for limiting the number of times said electromagnetic means may be actuated and operative therewith, and means adapted to be actuated b y said lastmentioned means for rendering said control system ineffective when combustion fails to take place during the last actuation of said electromagnetic means.

4. The combination with a heating system including means for feeding fuel and an igniter, of a control system therefor comprising means for controlling said fuel-feeding means and igniter to attempt to initiate combustion in said firstmentioned means at predetermined temperature conditions, electromagnetic means for rendering said second-mentioned means effective, intermittent circuit controlling means for causing the energization of said electromagnetic means intermittently whereby it is actuated at selected intervals for periods of short duration, electrically controlled timing means comprising a synchronous motor the operation of lwhich depends only on the frequency of an alternating current independent of any voltage variation in said current for actuating said fourth-mentioned means to produce the desired intervals, means for limiting the number of times said electromagnetic means may be actuated and operative therewith, and means adapted to b e actuated by said last-mentioned means for rendering said control system ineifective when combustion fails to take place during the last actuation of said electromagnetic means.v

5. The combination with a heating system including means for feeding fuel, ignition means therefor, of a control system therefor comprising means for controlling said fuel-feeding means and said ignition means, motor-operated timing means for attempting Ito linitiate combustion for 'periods of predetermined short durationatnefinite predetermined` selected intervals, `'anda pawl and ratchet means operated by said controlling means to disable' saidcontrol system whenfcombustion fails to take place', said disabling'rne'ans being adapted to be manuallyre'set to render said ,control system effective, and means operatively y associated'with said control system and responsive to combustion for maintaining said 'fuel-feeding' 'means in operation independently of said-motoroperated timing cam mechanism when combustion is established. i l

6. The combination with a heating system including means for feeding fuel, ignition means therefor, of a control system comprising means for controlling said'fuel-feeding means and said ignition means, timing cam mechanism for operating said controlling means for attempting to initiate combustion a predetermined number of times for periods of predetermined short duration at definite predetermined selected intervals, and a pawl and ratchet means operated by said thirdmentioned means and rendered effective during the last operation thereof to disable said control system when combustion fails to take place, said fourth-mentioned means having a mechanical locking pawl adapted to be manually reset to render said control system eifective, and means operatively associated with said control system and responsive to combustion for maintaining said fuel-feeding means in operation independently of said timing ca`m mechanism when combustion is established.

7. The combination with a heating system including means for feeding fuel, an igniter, of a control system therefor comprising means for controlling said fuel-feeding means and igniter to attempt to initiate combustion at predetermined temperature conditions, electro-magnetic means for rendering said second-mentioned means effective, intermittent circuit controlling means for causing energization of said electromagnetic means intermittently whereby it is actuated at selected intervals for periods of short duration, electrically controlled timing means for operating said fourth-mentioned means to obtain the selected intervals, means for limiting the number of times said electro-magnetic means may be actuated and operative therewith, means adapted to be actuated by said sixth-mentioned means for rendering said control system ineffective when combustion fails to take place during the last actuation of said electro-magnetic means, and means rendered operative when combustion is established to simultaneously cause continuous energization of said electro-magnetic means to maintain said combustion and to -return said limiting means to its normally starting position.

8. A heating device including electrical means for feeding fuel, an igniter therefor, an electrical control for controlling said fuel-feeding means and igniter including a constant speed motor-operated timing switch mechanism and electromagnetic switch mechanism controlled thereby for intermittently energizing said fuel-feeding means and igniter at predetermined intervals for initiating combustion, temperature-responsive means movable between two positions and movable to one of said positions for rendering said fuel-feeding and igniter control effective under predetermined temperature conditions, and means responsive to combustion conditions for controlling said electromagnetic switch mechanism to maintain the fuel-feeding means energized when combustion is established independently of the operation of said motor-operated timing switch mechanism, said temperature responsive means being movable to the other position under'other predetermined temperature conditions for controlling said electromagnetic switch mechanism to deenergizesaid fuel-feeding means.

9. A heating device including electrical means for feeding fuel, electrical means for igniting-said fuel, an electrical control for said fuel-feeding means and said igniting means including a constant-speed motor-operated timing switch mechanism and electromagnetic switch mechanism controlled thereby for controlling said feeding means and ignition means for intermittently energizing the same atfpredetermined intervals for initiating combustion, temperature-responsive means movable between two positions and movable to one of said positions for rendering said fuel-feedingand ignition control effective under predetermined temperature conditions, and means responsive to combustion conditions for deenertric motor operated timing switch mechanism for controlling the energization of said electromagnetic switching means for repeating said ignition attempts a predetermined number of times at definite predetermined selected intervals, and means operative to control the energization of said electromagnetic circuit controlling means to hold said fuel feeding means in continuous operation-and to prevent the repetition of said ignition attempts independently of said motor operated timing switch mechanism-when combustion is established.

l1. The combination with a heating system including means for feeding fuel, an igniter therefor, a control system therefor, comprising a source of electrical energy, means including an electroresponsive switch energized from said source for controlling said fuel feeding means and igniter to attempt to initiate combustion, intermittent circuit controlling mechanism for intermittently deenergizing and reenergizing said electroresponsive switch to repeat said ignition attempts at selected intervals, means movable from a starting position and operative with said electroresponsive switch for limiting the number of repetitions, combustion responsive means for deenergizing said igniter when combustion is es-A tablished, and electrical means rendered operative by said combustion responsive means when combustion takes place for causing said limiting means to return to the starting position whereby said combustion is maintained.

12. The combination with a heating system including means for feeding fuel, an igniter therefor, of means including an electroresponsive device for controlling said fuel feeding means and said igniter to attempt to initiate combustion, intermittent circuit controlling mechanism for deenergizing and reenergizing said electroresponsive device to repeat said ignition attempts at selected intervals, means movable from a starting position through a series of steps for limiting the number of repetitions of ignition attempts, electroresponsive means for causing said limiting means to return to the starting position, and combustion responsive means for rendering said electroresponsive means effective when combustion is established.

JAMES McK. RElLEY.

AGl 

